1. Field of the Invention
The invention relates to devices for human hair destruction and removal by "electrolysis" or "electrolytic depilation".
2. Prior Art
The removal of hair from areas of the human body where it is not desired has long been practiced by chemical, electrical and purely mechanical means. Historically, such hair removal has been more of an art than a science. However, more recently, relatively safe and effective means have evolved. In addition to the mechanical methods, which are not suitable in many cases and are not permanent, there are chemical and electrical methods. Chemical methods may or may not be permanent and, if sufficiently stringent to inhibit regrowth, are likely to produce skin irritations and other medically undesirable effects.
Among the electrical devices for depilation are some which generate and supply light energy in pulsed form to the follicle entrance to produce photoepilation or photocoagulation. Examples of this prior art are found in U.S. Pat. Nos. 3,693,623 and 3,834,391.
A prior art U.S. patent more germane to the specific type of electrolytic depilatory device of the invention is U.S. Pat. No. 3,815,603. In that reference a unidirectional current with a superimposed radio frequency component or modulation is applied through a well known filament electrode to destroy the papilla associated with the root of the hair to be destroyed.
The flow of the unidirectional current by itself is known to be effective in destroying the papilla chemically by dissociating tissue water into hydrogen cations and hydroxide anions in the immediate vicinity of the papilla (galvanic electrolysis). To insure a suitable charge concentration, such electrolytic depilatory devices customarily employ a "wet pad" or body electrode in electrical contact with an adjacent part of the body as a positive electrode. The filament electrode or needle is the negative electrode, and the depilatory action is then a function of the current-time integral.
Discomfort associated with electrolytic (galvanic) depilation is generally in proportion to the effectiveness of the action.
In describing the invention hereinafter, a prior art depilation circuit employing a number of filamentary electrodes (needles) is described as background. Practical devices of the type generally use multiple needles. Therein lies the source of an additional problem; namely, the unequal division of current among the plural needles when a common current source is employed. This is true even if a constant current source is employed as suggested in the aforementioned U.S. Pat. No. 3,815,603.
That, and other disadvantages of the prior art are uniquely remedied by the combination of the invention, as will be described hereinafter.